Exhaust valves implementing a flap to regulate flows of fluid through an opening are known. However, particularly within respiration therapy equipment, such valves typically require mechanism for holding the flap securely in place during use that are relatively costly. For example, such valves may require one or more of ultrasonic welding, snap-fitting retainer pieces, expensive adhesives, intricate assembly techniques, and/or other costly mechanisms for holding a valve flap in place.